the check suggests an alternative: operator+ on std::experimental::simd
objects.

Otherwise, it just complains the intrinsics are non-portable (and there are
P0214 alternatives).

Many architectures provide SIMD operations (e.g. x86 SSE/AVX, Power AltiVec/VSX,
ARM NEON). It is common that SIMD code implementing the same algorithm, is
written in multiple target-dispatching pieces to optimize for different
architectures or micro-architectures.

The C++ standard proposal P0214 and its extensions cover many common SIMD
operations. By migrating from target-dependent intrinsics to P0214
operations, the SIMD code can be simplified and pieces for different targets can
be unified.

Refer to P0214 for introduction and motivation for the data-parallel standard
library.